Dell 5570 (Sierra) supported?

Bjørn Mork bjorn at
Wed Nov 26 00:41:03 PST 2014

Dan Williams <dcbw at> writes:
> On Tue, 2014-11-25 at 20:03 +0100, Manuel Lauss wrote:
>> > On Tue, 2014-11-25 at 19:54 +0100, Manuel Lauss wrote:
>> >
>> >>            |    power state: 'low'

Ouch.  Now I remembered where I last heard about this modem...

And it most likely does not have anything to do with the modem at all.
It is some Dell laptop rfkill feature we just don't know how to

>> Well, rfkill list shows only bluetooth and wlan (and nfc card reader).
>> wwan is enabled in BIOS; the dell airplane mode switch acpi device node
>> doesn't do anything (tried to poke all methods with acpi_call).
> One more thing to double-check: is the SIM slot under the battery, and
> if so is the battery inserted and correctly seated?  My laptop (an HP,
> not a dell) has some kind of BIOS interlock so that when the battery is
> removed (or poorly secured) it will rfkill the WWAN card automatically
> to prevent SIM hotswapping.

Smart :-)  Yes, that sounds like something to verify.

But the fact that there is no wwan switch in the "rfkill list" output is
really a strong indication that we lack support for the wwan switch in
the dell laptop driver (for this laptop variant - it obviously works for
older Dell laptops).

If this is correct, then it really isn't an MM or modem driver issue.
It's more a problem for the platform-driver-x86 at list.

You could use the extremely useful Sierra AT commands to verify that the
problem is in fact external to the modem:

1) switch the modem to QMI mode:
     # echo 1 > /sys/bus/usb/devices/1-10/bConfigurationValue

2) use a terminal application to talk to the AT command port (might be
   different from ttyUSB2):
     $ minicom /dev/ttyUSB2

3) Get the detailed low power status:

I dont' remember if that command is password protected or not.  If it
is, then you could try AT!ENTERCND="A710" first.  But Dell might have
changed that password from the default.


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